Various formes of clutches are well known in the vehicle industry for coupling engines to transmissions. These clutches can be categorized in differing manners, but one common categorization of the clutches is "wet" and "dry". A dry clutch is provided with a friction material which is maintained in a dry state and is adapted to be clamped between a reaction surface and a pressure plate when the clutch is engaged. As the design torque loading increases it is either necessary to increase the diameter of the clutch plate, to use multiple clutch plates, or to increase the force of clamping, requiring harder friction materials in order to reduce excessive wear.
Typically, because of the various design criteria set forth above, a dry clutch used in a high-torque environment requires a high pedal effort for its disengagement. Also, large diameter friction disks have high inertia forces which cause excessive drag forces during the shifting of gears. High inertia forces of the clutch also complicate the design of synchromesh transmissions. It has long been recognized in the industry that improved clutch service life can be achieved by utilizing wet clutches. In a wet clutch a cooling oil is passed over the surface of the friction material to prevent it from overheating and rapidly wearing. A typical wet clutch is hydraulically operated, having a plurality of interleaved clutch disks and spacers and operates in a sealed compartment. While this form of construction has improved durability characteristics over the aforementioned dry clutches, it has other drawbacks in that it is necessary to provide a sealed drive train compartment between the engine and the front of the transmission.